北京大学科维理天文与天体物理研究所

Featured Science

An international team of researchers have found an infrequent variation in the brightness of a forming star. This 18-month recurring twinkle is not only an unexpected phenomenon for scientists, but its repeated behavior suggests the presence of a hidden planet.

Ran Wang’s group works on the ISM property of far-infrared (FIR) luminous quasars above redshift 5.7. Their recent paper studying the gas dynamics of a luminous z = 6.13 quasar ULAS J1319+0950 revealed by ALMA high resolution observations (a graduate student Yali Shao as the leading author) was highlighted by the American Astronomical Society (aasnova.org) on 6 September 2017.

An international collaboration of astronomers from PUC Chile, CASSACA and KIAA Beijing set out to complete a full census of nearby growing black holes, by using observations carried out in the X-ray band. Similarly to what is typically used for radiographies in hospitals, such observations can see through regions in space that are blocking visible light, such as the dusty regions around black holes. With each observation, performing these “space radiographies”, they could measure the amount of material around the black hole, and then study its evolution.

KIAA postdoc fellow Hao-Ran Yu and his research team completed the World’s largest N-body simulation “TianNu” on the Chinese Tianhe-2 supercomputer. This 3 trillion particle N-body simulation coevolve the cold dark matter and neutrino fluids throughout the cosmic evolution, and discovered the differential neutrino condensation effect, which opens the path to an independent cosmological measurement of neutrino masses.

The team, comprising investigators from Italy, the UK, China, Germany, Chile and have completed a large survey of molecular gas in nearby galaxies using the 12m APEX telescope in Chile. The APEX Low-redshift Legacy Survey of MOlecular Gas (ALLSMOG) has observed the Carbon Monoxide (CO) molecule in a sample of 97 galaxies in the local Universe. The ALLSMOG data provide important information on the cold molecular gas content of these galaxies which have been well characterized in terms of their star-formation rates, gas-phase metallicities and atomic HI gas masses.

An international team of astronomers from China and Chile use NASA's NuSTAR telescope to observe the penetrating high-energy X-ray emission from 52 galaxies. They find that in the late stages of galaxy mergers, so much gas and dust falls toward a black hole that the extremely bright AGN is enshrouded. This study helps confirm the longstanding idea that an AGN's black hole does most of its eating while enshrouded during the late stages of a merger.